DE2430874A1 - STATOR WINDING ARRANGEMENT, IN PARTICULAR FOR USE FOR THREE- OR MULTI-PHASE POLE-SWITCHING SYNCHRONOUS MACHINES - Google Patents

Description

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BBC Aktiengesellschaft Brown, Boveri & Cie., Baden (Switzerland)

Stator winding arrangement, in particular for use for three- or multi-phase pole-changing synchronous machines.

The invention relates to a stator winding arrangement, in particular for use in three- or multi-phase pole-changing synchronous machines with nested bar windings.

As is well known, the conductors of a winding of an electrical machine are distributed in different slots on the stator circumference and the individual voltages generated in the conductors must be added taking their phase position into account (see:
Bödefeld and sequence "Electrical Machines", sixth edition, pages 16 3 - 169, and R. Oberholzer "Construction
electrical machines, II. synchronous machines ", pages 18 - 40),

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The resulting voltage of a stator winding is less than the number of conductors times the voltage of a conductor results. The algebraic sum of the individual stresses must therefore be multiplied by a factor to obtain the to give real tension (geometric sum). This factor j ^ is called the winding factor and is by determines the geometric design of the winding.

In long windings, where a step shortening or lengthening is made to suppress certain harmonics in the voltage curve and the two coil sides of a coil are no longer one pole pitch L apart, the winding factor of one winding is one phase

-, wobex

w the spool width, also called the winding pitch, in slot pitches

'Kö the pole pitch, in slot pitches

q the number of slots per pole and phase, and

© <is the electrical angle that corresponds to the mechanical angle corresponds between two adjacent grooves.

W / L »

The factor k _p = sin - = - j- is called the visual factor and that

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Ratio s = -? = - referred to as tendon. To be in the tension

Lp

To eliminate the V-th harmonic curve, the winding step w must be shortened by the -r- th amount of the pole pitch * ^ (or extended). Often one chooses -S- = 0.81 or

Zp

- = r- = 1 »2, with the 5th and 7th harmonics then largely Lp

be suppressed.

In pole-changing synchronous machines, such as those in particular Finding use in pumped storage systems, the problem of tendon is complicated by being in a single machine two different numbers of poles for two different speeds must be paired with each other. It'll be common For the two different numbers of poles, two separate, stringed windings are used, either one on top of the other or can be nested windings. For great tensions and performances, the nested ones Windings, which can be either loop or wave windings, have proven particularly advantageous (Brown Boveri Communication 6/7, 1970, p. 299).

In the known winding arrangements with nested wave windings used in pole-changing synchronous machines, the winding step w (coil width) of winding 1 is the _{same as winding step W 2} of winding 2, ie

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w = w. As a result of this choice of winding steps w, w, only one of the tension values s, s can be freely selected, whereas the other can be freely selected by the selected value and the pole pitches t. ρ ^un Lp is uniquely determined. The following relationships apply:

- = p. 6

1 1 P ₁ ; w ₂ =

so that

For the common winding step W = W ₁ = W, one is usually chosen that lies between the two optimal winding steps for the relevant number of poles, taking into account the harmonics to be suppressed. In this way, most of the time the winding pitch for one of the windings is underestimated, while that for the other winding is overstretched. Often one of the two windings is disadvantaged to a considerable extent.

In the case of nested loop windings according to the prior art, winding steps are used for the two windings chosen, which differ from each other by two divisions. The connection of the rods of the lower layer with the In this case, the bars of the upper layer can be easily passed through with conventional straight connecting eyelets.

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to lead. With certain number of pole pairs, a loop winding arrangement results this kind of better vision values.

With many, in a pole-changing synchronous machine too pairing speeds or pole numbers, one is in the choice of the Wrapping steps in spite of the aforementioned possibility narrowed, and it can be with this choice and when using the known connection arrangements both in terms of on the tendon, the harmonic content, the tendon factor and thus the winding factor, as well as in relation to the losses result in very unfavorable values.

The prior art winding assemblies described in pole-changing synchronous machines are used today, are therefore characterized by:

a) Wave windings with the same winding steps and the resulting restriction only such pole numbers or To be able to pair speeds in a synchronous machine that are very close to each other ^

b) loop windings with the same winding steps or winding steps that differ from one another by two slot pitches;

c) freedom in the choice of the tension value of one of the windings;

d) by choosing the tension value for one of the windings,

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a clearly determined, often unfavorable vision value for the other winding;

e) a frequently occurring undershoot of one winding and corresponding overshoot of the other winding;

f) unwanted harmonics in one and / or the other Winding;

g) as a result of the unfavorable vision values, unfavorable values the tension factor, the winding factor and the losses; and

h) conventional connection arrangements with straight eyelets.

The object of the invention is to avoid the disadvantages of the previously known and to provide a stator winding arrangement with two separate, to create interleaved windings that are suitable for use in three- or multi-phase pole-changing Synchronous machines are suitable, which have an additional degree of freedom in all pairs of poles that occur in practice the choice of pairable pole numbers or speeds, the winding steps and the tension values, and both in with respect to the harmonic content, the chord factor and thus the winding factor as well as with regard to the losses are favorable Values for both windings are possible, and which is further developed by one for each winding to bridge the intervals conductor bars that are to be connected to each other are

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formed a novel connection arrangement.

This task is accomplished with the help of the stator winding arrangement of the The type mentioned at the outset is achieved in that the winding steps of the two windings are separated by an integer even Distinguish constant C, according to the relationship:

C = W ₁ - W ₂ ,

where for wave windings the constant C has the values + _2, +4, "_ + 6 etc., with loop windings the constant C the values -2.0, + / *, _ + 6 etc., where furthermore w., W are the winding steps of the Windings are 1 and 2, and w, w "and C are expressed in slot pitches are, and that for each winding one to bridge the distances between the rods to be connected of the lower Layer with the corresponding rods of the upper layer formed connection arrangement is provided, the at least has oblique eyelets in one of the windings.

Exemplary embodiments of the subject matter of the invention are given below explained with reference to the drawing. It shows:

Fig. 1 shows a loop winding arrangement according to the prior art

Technique in which the winding pitch of the first • winding differs from the winding pitch of the second winding distinguishes between two groove divisions;

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ORIGINAL INSPECTED

2 shows an embodiment of a loop winding arrangement according to the invention, in which the winding step of the first winding is different from the winding step of the second Winding differs by two slot pitches;

3 shows an embodiment of a wave winding arrangement according to the invention, in which the winding step of the first winding is different from the winding step of the second Winding differs by four slot pitches;

4 shows the slot assignment of windings 1 and 2 in the winding arrangements according to FIGS. 1, 2 and 3;

5 shows a connection arrangement with oblique eyes made from round bars for use in a winding arrangement with two windings, the winding steps of which differ by two slot pitches;

6 shows an arrangement similar to the arrangement according to FIG. 5, the angled eyelets being made from flat bars;

7 shows a schematic representation of the arrangements according to FIGS. 5 and 6;

8 shows an arrangement similar to the arrangement according to FIG. 5,

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The winding steps of the two windings are distinguished by four slot pitches; and

FIG. 9 shows a schematic representation of the arrangement according to FIG Fig. 8.

In the following, the index relates to winding 1 and index 2 to winding 2. Es designated:

W is the first approximate value of the step, in groove divisions

w the winding step in slot pitches,

ρ is the number of pole pairs,

η is the speed in revolutions per minute,

Lp is the pole pitch in slot pitches,

S the desired longing,

s the actual longing,

Q is the number of grooves,

q the number of slots per pole and phase, and

f is the frequency of the generated alternating voltage.

The following relationships apply:

5098 4 9/02 3 2

/ ^Z

If the vision values s, s "the theoretically optimal vision values S .., S "are supposed to be the last relationship

S S

_w _ _{w =} 9 (_JL _ -2.)

^W l ^W 2 2 points

1 "2 2 ^ p ₁ P ₂ 120 f ^w l" l ^ 2 "2 ^y

From this relationship it can be seen that the choices made in the prior art wave winding arrangements equal winding steps w = w "from the point of view of an optimal Tensioning of the two windings is only justified from the point of view of

^S l ^S 2 ^P 2 ^S 2
if - = ■ = -, i.e. - - - ^ - ,
P ₁ P ₂ 'P ₁ S ₁

ⁿ l ^S 2
or if S η = S ₉ n ₉ , ie - ⁼ ö "~»

■ L Jl '£ ■ t- 0 ι

since only in this case w - w becomes equal to zero.

If these conditions are not met, which is true for most cases, w - w "is no longer zero, but a value of the given values of P ₁ , p", S, S- and Q from the relationship

S, S ".

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- li -

can be calculated and which in many cases of considerable Can be great. For this reason, wave windings • according to the prior art are only very close for pairing Corresponding pole numbers or speeds are suitable (e.g. 18/20; 22/24 etc.).

According to the invention, the constant C assumes the values + 2, +4, +6 etc. in the case of winding arrangements with two wave windings. The values s and s are visual values that differ from the theoretically optimal visual values S. and. S ₂ differ only to a small extent.

The selection of the winding steps, which differ from one another by two slot pitches, in the winding arrangements with two loop windings according to the prior art has a similarly very restrictive effect in the construction of such winding arrangements and results in unfavorable strain values for most of the pole numbers paired in a pole-changing synchronous machine. According to the invention, in the case of loop windings, the constant C can assume not only the value +2, but also the values 0, -2, _ + 4, +6, etc., the values s and s differing from those taking into account the The harmonics to be suppressed are also only slightly below the predetermined, theoretically optimal visual values S ₁ and S _2.

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divorce.

In the drawings, the same components are denoted by the same reference numerals.

The winding arrangement of Fig. 1 shows two prior art nested loop windings formed in the art 1 and 2. The data concerning the two windings are as follows:

Winding 1 = 288 18th Winding 2 = 288 24 Q = 16 .94 Q = 12 .79 ^2p i = 375 2P ₂ = 500 ⁿ i = 17 ⁿ 2 = 19 ^W l "A" ^W 2 % . ^w i. ^X Px . ^W 2. ^S l ^S 2

The winding steps w, w of the windings differ by two slot pitches, namely W ₂ - w. = 19 - 17 = 2.

The ends of the rods 3 of the lower layer are in this Arrangement immediately below the ends of the rods 4 of the upper layer, to which they must be connected, so that the

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necessary connection with the schematically illustrated conventional straight connection eyes 5 in a simple manner
can be done. However, of the vision values s = .94 and S ₂ = »79, only s comes close to the vision value S = 0.81, which is favorable from the point of view of the harmonic content. The winding 1
is therefore _{unfavorably longed with S 1} = .9t, whereas the winding 2 with S ₉ = .79 has an almost optimal longitude value.

Fig. 2 shows an inventive embodiment of a
Winding arrangement with two nested loop windings 1 and 2. The data relating to the two windings are as follows:

Development 1 = 120 15th Q = 8 .73 2P ₁ = 750 ⁿ i s 11 V = £ - = Tp ₄ r_ ■ " ⁵ I.

Development 2 = 120 = 12 Q = 10 = .75 2p ₂ = 600 n ₂ = 9 ^W 2 " ² P ₂ ^Z Pt . ^W 2
^ -_ ^S 2

The winding steps w, w «of the windings 1 and 2 differ also in this case by two slot divisions, namely:

w - w = 11 - 9 = 2. The bars 3 of the lower layer are with

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the bars t of the upper layer of the winding 1 on one side
connected to the oblique eyelets 6, whereas on the other side
straight lugs 5 are provided. The winding 2 has only straight eyelets 5. The vision values S ₁ = .73 and s = .75 differ only slightly from the value S = 0.81, which is favorable from the point of view of the harmonic content.

Fig. 3 shows an inventive embodiment of a
Winding arrangement with two nested wave windings 1 and 2. The data relating to the two windings are as follows:

Winding 1 Q = 120 2ώ, = 8

U ₁ = 750 W ₁ = 11

Winding 2 = 120 12th Q = 10 1.25 2p ₂ = 600 ⁿ 2 = 15 ^W 2 = -2- =
2P ₂ = - - = ^S 2

= 15

^W l

~ - = .73

The winding steps w., W _{2 of} the windings 1 and 2 differ by four slot pitches, namely: w. - w. ^S 15 - 11 ^s H. The bars 3 of the lower layer are aligned with the bars U of the upper layer of the winding 1 on both sides with angled eyelets 6

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bound. The winding 2 has only straight eyelets 5. In this case, too, the vision values s. = .73 and S ₂ = 1.25 differ only slightly from the values, which are favorable from the point of view of harmonic content, 0.8 and 1.2.

The arrangement of the conductor bars of the windings according to FIG. 1, 2 and 3 in the grooves of the stator bore is shown in FIG. In each groove there are two ladder bars, one bar each of each winding, arranged one above the other. These bars form two layers, an upper and a lower layer, where adjacent bars of one layer belong to different windings.

The connection of the rods of the lower layer with the corresponding ones Bars of the upper layer of a winding form a special feature in the winding arrangements according to the invention Problem, since the bars to be connected may be considerable Distances can be arranged from each other, and the obstacles located within these distances bypassed Need to become.

FIGS. 5, 6 and 8 show different embodiments of the connection arrangements according to the invention, the embodiment 5 and 6, which are shown schematically in FIG. 7, are intended for a winding arrangement at

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which the winding steps of the windings 1 and 2 differ by two slot pitches, whereas the embodiment according to FIG. 8, which is shown schematically in FIG. 9, is different relates to a winding arrangement in which the winding steps of the windings 1 and 2 are divided by four slot pitches differentiate. A connection arrangement according to the invention It is characteristic that one or both windings have oblique eyes. The oblique eyelets of a winding can be connected to each other be the same or different from each other. In addition, straight eyelets can also be present in both windings.

In the connection arrangement according to FIG can be accomplished with conventional straight eyelets 5. The end sections of the bars 3 and f of the winding 1 to be connected, however, lie in different planes which, however, are arranged parallel to one another The same projections of the bars of the winding 2. To bypass the straight eyelets 5, the U-shaped inclined eyelets 6 are used to connect the corresponding bars 3 and k of the winding 1. The inclined eyelets 6 are made of round ones

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Bars made and the connection is made as a round bar connection. bond.

The connection arrangement of Fig. 6 differs from 5 only in that the bars of the winding 1 have longer axial projections than the bars of the winding 2 have, so that the appropriate shape for the oblique eyes 6 is an "L-shape. The oblique eyes 6 are off in this case Flat bars are made, and the connection is called a flat bar connection

The connection arrangement according to FIGS. 8 and 9 is that according to Fig. 5 essentially the same, only it is, as mentioned above, used in a winding arrangement in which the winding steps of the two windings 1, 2 are four Differentiate slot pitches.

The round bars of this arrangement can have holes, if this is necessary for liquid cooling.

In the. Practice will be two taking into account the one to be suppressed Theoretically optimal values S and S are determined by harmonics. A first approximation C the constant C becomes the relationship

1 2 P ₁ p ₂

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determined. The integer even constant closest to C is chosen as C. The first approximate _{values W, W 2 of} the winding steps w, W ₂ are then calculated with the aid of the relationships

certainly. Integer odd values are then selected as winding steps w_, w. The final longing values s, _s s. Are then derived from the relationships

_s -Ü_ β -

determined.

It should be noted that there are various options for choosing the values S, S _2. For example, S ₁ = S ₂ = 0.8 or S ₁ = 0.8 and S ₂ = 1.2 or S ₁ = S ₂ = 1.2 can be selected. The winding step values that result from these tension values, which are equivalent from the point of view of the harmonic content, are different from one another and can easily be taken into account when choosing the final winding steps so that the tension values s .., S ₂

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come close enough to the desired values S, S _2.

The winding arrangements according to the invention, which are used in pole-changing Synchronous machines can be used, are characterized by:

a) Wave windings with unequal winding steps, whereby the winding steps of the windings differ by +2, +4, +6 etc. and thus offer the possibility of pairing two pole numbers or speeds in a synchronous machine that are further apart than in the machines was possible according to the state of the art;

b) Loop windings with the same or unequal winding steps, the winding steps of the windings differing by -2, 0, + ^, * ß , etc.;

c) extensive freedom in the choice of the tension values of both windings;

d) Avoidance of unwanted harmonics in both windings;

e) favorable values of the stretching factor, the winding factor and the losses; and

f) a novel connection arrangement for connecting the Bars of the upper layer with the bars of the lower layer of the relevant windings, at least one Winding oblique eyes are provided.

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Claims (7)

- 20 - 47/74 D Claims Stator winding arrangement, in particular for use for three- or multi-phase synchronous machines that can be retained in polar phases with two nested bar windings, characterized by the fact that the winding steps go through distinguish an integer even constant C, according to the relationship: C = where for wave windings the constant C takes on the values +2, +4, +6 etc., in the case of loop windings the constant C takes on the values -2.0, + ^ 4, +6 etc., where W ₁ , W _{2 are} the winding steps of windings 1 and 2, and W ₁ , W ₂ and C are expressed in slot pitches, and that for each winding a connection arrangement designed to bridge the distances between the bars of the lower layer to be connected with the corresponding bars of the upper layer is provided, which has oblique eyelets in at least one of the windings. 2. Arrangement according to claim 1, characterized in that 509849/0232 - 21 - 47/74 D. the oblique eyelets of a winding equal to one another or to one another are different. 3. Arrangement according to claim 1, characterized in that the bars of both windings have the same axial projections and that the connecting eyes of one of the windings are straight eyelets, whereas those of the other winding U-shaped oblique eyelets are. 4. Arrangement according to claim 1, characterized in that the bars of one winding have different projections in relation to the bars of the other winding, and that the connecting eyes of one of the windings are straight eyes, whereas those of the other winding are Z-shaped trained oblique eyes are. 5. Arrangement according to claim 1, characterized in that the chords s, and s _? of the windings 1 and 2 have values which are at least approximately predetermined optimum . Values S ,, Sp correspond to the harmonics in the Voltage curve that should be suppressed, have reference. 6. Arrangement according to claim 5, characterized in that 509849/0232 - 22 - 47/74 D. the values S, S are the same or different. 7. Arrangement according to claim 1, characterized in that the eyelets have bores for liquid cooling. BBC Public Company Brown, Boveri & Cie. 509849/0232 Blank page